Best Tonneau Cover for a RamBox Ram 1500: Check the Rails First

RamBoxes make a DT bed a different fitting job. The boxes are built into the bed sides, a cargo rail runs along the top of each bed wall beside the box lids, and the boxes end a little short of the tailgate. Cover makers answer with separate RamBox parts, and every one among our picks is for the 5 ft 7 in bed. The part you'd buy for a plain DT bed is often the wrong one.

We've reviewed each of the five in full, and each has a RamBox version we confirmed: four on Amazon listings, one on WeatherTech's own site. For the RetraxPRO XR and the AlloyCover, that confirmation is all there is: their RamBox fit rests on the listing and the maker, not on owner reports.

If your truck has no RamBoxes, our best tonneau cover for a Ram 1500 guide covers every DT bed and tailgate.

Five covers with a RamBox listing

Sort by your truck's year first. The listings below end in different years, and only two of them reach 2027.

• 2019-2022 with silver rails: the Ultra Flex. It's our top pick and the driest of the five by our scores. The RamBox listing is for the 5 ft 7 in bed, needs the silver cargo rails and says nothing about the multifunction tailgate, though RealTruck's page for the part says it works with or without one. Folded, the panels stand upright on prop rods clear of the cab.
• A hard folder for 2023 on: the BAKFlip F1. Fiberglass-reinforced polymer panels, 400 lb evenly distributed, a 5-year warranty and a RamBox listing that runs 2019-2026. It costs a little less than the Ultra Flex on this bed. On a split-gate truck, check with RealTruck first: Amazon's listing says it fits either tailgate, but RealTruck's notes for the same part say it doesn't suit the split gate.
• No drain tubes: the AlloyCover, a low aluminum tri-fold that WeatherTech sells for 2019-2027 DTs in versions with and without RamBox. WeatherTech says the hinges and a continuous side seal route water off, so there are no tubes to plumb. It's sold only by WeatherTech, so we earn nothing on it, and WeatherTech is silent on the split gate.
• Retractable: the RetraxPRO XR. A keyed latch holds it locked wherever you stop it, the slats carry 500 lb evenly distributed, and the warranty is limited lifetime. The RamBox listing fits either tailgate. It's the most expensive pick, and its T-slot rails are no rack answer here: Leitner, whose TONNEAU rack rides them, says its Ram parts don't work with RamBoxes.
• Least money: the Lo Pro, soft vinyl that rolls to the cab, listed for 2019-2027 with or without the split tailgate. It's the least expensive RamBox listing among our picks. There's no lock and no published load rating.

Silver rails or black: the check that comes first

Look along the top inside edge of each bed wall. Ram bolts a cargo rail there in one of two versions. The silver one is bare metal with a channel down its middle for the sliding tie-down cleats. The black one is painted, sits higher and has a wide flat top, which is what Ram's factory cover seals against. Trucks built with that factory cover usually got the black rails, but not every one did, so check your own bed rather than going by trim or package.

It matters because RealTruck ties all four of its RamBox picks to the silver rails. Its page for the Ultra Flex RamBox part says the silver rails are a must and the black track system won't work, and its product index lists the F1, PRO XR and Lo Pro RamBox parts for trucks with the silver rails. Of the four Amazon listings, only the Ultra Flex's mentions rails, and WeatherTech's page for the AlloyCover doesn't mention them at all. Owners back RealTruck up: on black rails, a RamBox F1's rails wouldn't attach, and Retrax covers went on only after the swap. A RealTruck rep on the 5thGenRams forum says most RamBox covers need the silver rails. We'd plan on them for any cover on this list.

The swap is a bolt-on job: the silver rails use the same holes, and you reuse the bolts from the black ones. Have a Mopar parts counter order the silver rails by their own part number rather than by your VIN, since a VIN lookup can return the black rails your truck shipped with, and allow for a wait: the silver rails have sat on backorder for weeks, sometimes months. If you're still buying the truck, ask the dealer to swap the rails before delivery. And if you sell the factory cover later, the black rails go with it; it won't work without them.

Which RamBox listing fits your year and tailgate

Every column is a RamBox version for the 5 ft 7 in bed, read on the Amazon listing or, for the AlloyCover, on WeatherTech's page for the Ram, with RealTruck's notes where they add to the listing.

The years cut the field fast. A 2023-or-later truck is past the Ultra Flex listing. A 2026 truck is named by the F1, AlloyCover and Lo Pro, and by the PRO XR's fitment bullet though not its title. A 2027 truck is named only by the AlloyCover and the Lo Pro; for anything else, ask the seller. Each Amazon listing here calls the truck the Ram 1500 from 2019 on, and Ram also sold the older Ram 1500 Classic from 2019, so our fitment notes say where a listing doesn't name the body style.

The split tailgate is where the listings get thin. The PRO XR and Lo Pro RamBox listings say they fit with or without it. The Ultra Flex RamBox listing doesn't say, though RealTruck's page for that part says it works with or without the split gate, and one owner with RamBoxes and the split gate fitted one with no trimming. The F1 is the open dispute between Amazon's listing and RealTruck's notes. Whatever the listing says, expect gaps at the ends of a split gate that you'll want to fill.

How the five compare on paper

None of the five makers publishes a cover weight, and each describes a clamp-on install with no drilling into the bed on most trucks. The F1 and PRO XR have drain tubes to route to the bed's drain holes, and some PRO XR installs drill through the plastic plugs at the front of the bed to reach them.

The load figures assume weight spread across the closed cover, and WeatherTech's own manual says to put nothing on the AlloyCover at all. They describe panel strength. None of them turns a lid into a shelf for a toolbox or a cooler.

The gap between the RamBoxes and the tailgate

Each RamBox stops short of the tailgate, and that leaves an opening at both back corners of the bed. A cover's seals ride the box tops and the gate, so the corners stay open unless you fill them. The fix is cheap: dense stick-on foam or weatherstrip, cut to fit and stacked until it closes the gap, held with good double-sided tape. Some covers ship a strip for the job; an Ultra Flex RamBox owner found one in the box to cut for each side of the tailgate. Foam cuts the water a lot. It won't make the bed dry in a hard, windy storm or a car wash, and on a split gate some water can still get past the top of the gate.

Among the picks, the Ultra Flex has the best water record of the five, on any truck: it reads moderate on our leak-risk gauge, keeps the bed dry more often than not, and lets in a little when it doesn't. The few F1 owners who describe their own bed mostly report little or no water, too few reports for a gauge reading. The AlloyCover also reads moderate; expect a drip at the tailgate in a hard storm. A RetraxPRO XR usually lets in a little, mostly along the side rails and then at the tailgate. The Lo Pro is as dry as its vinyl is tight.

Keep anything that can't get wet up off the floor at the back. Water that gets past the corners runs along the bed floor toward the drain holes; a bin or a raised mat keeps cargo out of its path.

RamBox lids, bed space and the rear window

Open both RamBox lids all the way after any install. The cover's side seals sit on the bed caps right beside the lids, and a seal that reaches too far can stop a lid short or make it pop as it closes. That complaint centers on Retrax's MX covers with the earlier side gasket, whose owners trimmed or reshaped it to free the lids. Those are different covers from the PRO XR, whose RamBox fit rests on its listing alone, so check the lids before you call the job done.

The 5 ft 7 in bed doesn't leave much floor to give away. The Ultra Flex stack takes roughly the front 8 in by one owner's estimate, leaving about 59 in of the 67.4 in bed open, but standing upright it blocks much of the rear window while you drive with it folded. The F1 can stop at two-thirds open on buckle straps, which keeps its stack away from the rear window. The AlloyCover's two rear panels fold onto a front one that doesn't lift; if the three are equal, the stack covers about 22 in and leaves about 45 in, so lift the cover off for anything longer. The PRO XR canister costs about 13 in for good, by owner measurements on other trucks, leaving about 54 in of full-height floor. Rolled up, the Lo Pro gives back nearly all of it.

One habit for the Lo Pro: shut the tailgate first, then roll the cover closed. Closing the gate under a closed Lo Pro bends the rear gasket.

Covers that stop short of a RamBox bed

• Ruled out by their makers: the LEER HF650M (LEER says it won't work with RamBox or the 60/40 multifunction tailgate), the Peragon Landmark, the Tyger T3 Soft Tri-Fold, the Rough Country Low Profile and the Gator EFX. Peragon says its cover won't fit RamBox beds, Tyger's site says its DT T3 won't fit RamBoxes, Rough Country says the Low Profile doesn't fit them, and RealTruck lists no RamBox version of the EFX, whose 6 ft 4 in listing rules RamBoxes out.
• RamBox in the title only: the BAK Revolver X4s. One 5 ft 7 in listing says w/RamBox in Amazon's title, but RealTruck's page for that part says nothing about RamBox, and RealTruck says its standard 5 ft 7 in part isn't compatible with the multifunction tailgate. Owners do run X4s covers on RamBox, split-gate trucks, but it isn't one of our picks here: ask RealTruck and check fit for your truck before you order.

Owners also run the TruXedo Sentry CT and the BAKFlip MX4 on RamBox trucks, but we couldn't confirm a RamBox listing for either. Search for a RamBox Sentry CT or a RamBox MX4 and check fit for your truck. We rate the MX4's leak risk high, so it wouldn't be our pick here anyway.

If you'd rather keep the black rails, one owner says the DiamondBack SE hard cover mounts on either kind. We haven't reviewed it, so check fit for your truck.

Which one we'd put on your RamBox truck

Check the rails, then the year. On a 2019-2022 truck with the silver rails, buy the Ultra Flex. From 2023 on, take the F1 if you want a hard folder from Amazon, or the AlloyCover if you'd rather skip drain tubes and buy direct from WeatherTech; either way, settle the split-gate question with the maker before you pay.

Spend up for the PRO XR only if you want a cover that opens with the tailgate shut and locks partway. The Lo Pro covers a RamBox bed for the least money, as long as you can live without a lock. With black rails, budget for the silver ones and the wait before the cover goes on.